Add ARM NEON intrinsic optimizations for SincResampler.

media/base/sinc_resampler.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_SINC_RESAMPLER_H_
 #define MEDIA_BASE_SINC_RESAMPLER_H_
 
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/aligned_memory.h"
 #include "base/memory/scoped_ptr.h"
-#include "build/build_config.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // SincResampler is a high-quality single-channel sample-rate converter.
 class MEDIA_EXPORT SincResampler {
  public:
   // Callback type for providing more data into the resampler.  Expects |frames|
   // of data to be rendered into |destination|; zero padded if not enough frames
   // are available to satisfy the request.
@@ skipping 15 matching lines @@
   // Flush all buffered data and reset internal indices.
   void Flush();
 
  private:
   FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve);
   FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark);
 
   void InitializeKernel();
 
   // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are
-  // linearly interpolated using |kernel_interpolation_factor|.  The underlying
-  // implementation is chosen at run time based on SSE support.
+  // linearly interpolated using |kernel_interpolation_factor|.  On x86, the
+  // underlying implementation is chosen at run time based on SSE support.  On
+  // ARM, NEON support is chosen at compile time based on compilation flags.
   static float Convolve(const float* input_ptr, const float* k1,
                         const float* k2, double kernel_interpolation_factor);
   static float Convolve_C(const float* input_ptr, const float* k1,
                           const float* k2, double kernel_interpolation_factor);
   static float Convolve_SSE(const float* input_ptr, const float* k1,
                             const float* k2,
                             double kernel_interpolation_factor);
+  static float Convolve_NEON(const float* input_ptr, const float* k1,
+                             const float* k2,
+                             double kernel_interpolation_factor);
 
   // The ratio of input / output sample rates.
   double io_sample_rate_ratio_;
 
   // An index on the source input buffer with sub-sample precision.  It must be
   // double precision to avoid drift.
   double virtual_source_idx_;
 
   // The buffer is primed once at the very beginning of processing.
   bool buffer_primed_;
@@ skipping 17 matching lines @@
   float* const r3_;
   float* const r4_;
   float* const r5_;
 
   DISALLOW_COPY_AND_ASSIGN(SincResampler);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_SINC_RESAMPLER_H_